1 /* 2 * MachZ ZF-Logic Watchdog Timer driver for Linux 3 * 4 * 5 * This program is free software; you can redistribute it and/or 6 * modify it under the terms of the GNU General Public License 7 * as published by the Free Software Foundation; either version 8 * 2 of the License, or (at your option) any later version. 9 * 10 * The author does NOT admit liability nor provide warranty for 11 * any of this software. This material is provided "AS-IS" in 12 * the hope that it may be useful for others. 13 * 14 * Author: Fernando Fuganti <fuganti@conectiva.com.br> 15 * 16 * Based on sbc60xxwdt.c by Jakob Oestergaard 17 * 18 * 19 * We have two timers (wd#1, wd#2) driven by a 32 KHz clock with the 20 * following periods: 21 * wd#1 - 2 seconds; 22 * wd#2 - 7.2 ms; 23 * After the expiration of wd#1, it can generate a NMI, SCI, SMI, or 24 * a system RESET and it starts wd#2 that unconditionaly will RESET 25 * the system when the counter reaches zero. 26 * 27 * 14-Dec-2001 Matt Domsch <Matt_Domsch@dell.com> 28 * Added nowayout module option to override CONFIG_WATCHDOG_NOWAYOUT 29 */ 30 31 #include <linux/module.h> 32 #include <linux/moduleparam.h> 33 #include <linux/types.h> 34 #include <linux/timer.h> 35 #include <linux/jiffies.h> 36 #include <linux/miscdevice.h> 37 #include <linux/watchdog.h> 38 #include <linux/fs.h> 39 #include <linux/ioport.h> 40 #include <linux/notifier.h> 41 #include <linux/reboot.h> 42 #include <linux/init.h> 43 #include <linux/io.h> 44 #include <linux/uaccess.h> 45 46 #include <asm/system.h> 47 48 /* ports */ 49 #define ZF_IOBASE 0x218 50 #define INDEX 0x218 51 #define DATA_B 0x219 52 #define DATA_W 0x21A 53 #define DATA_D 0x21A 54 55 /* indexes */ /* size */ 56 #define ZFL_VERSION 0x02 /* 16 */ 57 #define CONTROL 0x10 /* 16 */ 58 #define STATUS 0x12 /* 8 */ 59 #define COUNTER_1 0x0C /* 16 */ 60 #define COUNTER_2 0x0E /* 8 */ 61 #define PULSE_LEN 0x0F /* 8 */ 62 63 /* controls */ 64 #define ENABLE_WD1 0x0001 65 #define ENABLE_WD2 0x0002 66 #define RESET_WD1 0x0010 67 #define RESET_WD2 0x0020 68 #define GEN_SCI 0x0100 69 #define GEN_NMI 0x0200 70 #define GEN_SMI 0x0400 71 #define GEN_RESET 0x0800 72 73 74 /* utilities */ 75 76 #define WD1 0 77 #define WD2 1 78 79 #define zf_writew(port, data) { outb(port, INDEX); outw(data, DATA_W); } 80 #define zf_writeb(port, data) { outb(port, INDEX); outb(data, DATA_B); } 81 #define zf_get_ZFL_version() zf_readw(ZFL_VERSION) 82 83 84 static unsigned short zf_readw(unsigned char port) 85 { 86 outb(port, INDEX); 87 return inw(DATA_W); 88 } 89 90 91 MODULE_AUTHOR("Fernando Fuganti <fuganti@conectiva.com.br>"); 92 MODULE_DESCRIPTION("MachZ ZF-Logic Watchdog driver"); 93 MODULE_LICENSE("GPL"); 94 MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR); 95 96 static int nowayout = WATCHDOG_NOWAYOUT; 97 module_param(nowayout, int, 0); 98 MODULE_PARM_DESC(nowayout, 99 "Watchdog cannot be stopped once started (default=" 100 __MODULE_STRING(WATCHDOG_NOWAYOUT) ")"); 101 102 #define PFX "machzwd" 103 104 static struct watchdog_info zf_info = { 105 .options = WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE, 106 .firmware_version = 1, 107 .identity = "ZF-Logic watchdog", 108 }; 109 110 111 /* 112 * action refers to action taken when watchdog resets 113 * 0 = GEN_RESET 114 * 1 = GEN_SMI 115 * 2 = GEN_NMI 116 * 3 = GEN_SCI 117 * defaults to GEN_RESET (0) 118 */ 119 static int action; 120 module_param(action, int, 0); 121 MODULE_PARM_DESC(action, "after watchdog resets, generate: 0 = RESET(*) 1 = SMI 2 = NMI 3 = SCI"); 122 123 static void zf_ping(unsigned long data); 124 125 static int zf_action = GEN_RESET; 126 static unsigned long zf_is_open; 127 static char zf_expect_close; 128 static DEFINE_SPINLOCK(zf_port_lock); 129 static DEFINE_TIMER(zf_timer, zf_ping, 0, 0); 130 static unsigned long next_heartbeat; 131 132 133 /* timeout for user land heart beat (10 seconds) */ 134 #define ZF_USER_TIMEO (HZ*10) 135 136 /* timeout for hardware watchdog (~500ms) */ 137 #define ZF_HW_TIMEO (HZ/2) 138 139 /* number of ticks on WD#1 (driven by a 32KHz clock, 2s) */ 140 #define ZF_CTIMEOUT 0xffff 141 142 #ifndef ZF_DEBUG 143 # define dprintk(format, args...) 144 #else 145 # define dprintk(format, args...) printk(KERN_DEBUG PFX ":%s:%d: " format, __func__, __LINE__ , ## args) 146 #endif 147 148 149 static inline void zf_set_status(unsigned char new) 150 { 151 zf_writeb(STATUS, new); 152 } 153 154 155 /* CONTROL register functions */ 156 157 static inline unsigned short zf_get_control(void) 158 { 159 return zf_readw(CONTROL); 160 } 161 162 static inline void zf_set_control(unsigned short new) 163 { 164 zf_writew(CONTROL, new); 165 } 166 167 168 /* WD#? counter functions */ 169 /* 170 * Just set counter value 171 */ 172 173 static inline void zf_set_timer(unsigned short new, unsigned char n) 174 { 175 switch (n) { 176 case WD1: 177 zf_writew(COUNTER_1, new); 178 case WD2: 179 zf_writeb(COUNTER_2, new > 0xff ? 0xff : new); 180 default: 181 return; 182 } 183 } 184 185 /* 186 * stop hardware timer 187 */ 188 static void zf_timer_off(void) 189 { 190 unsigned int ctrl_reg = 0; 191 unsigned long flags; 192 193 /* stop internal ping */ 194 del_timer_sync(&zf_timer); 195 196 spin_lock_irqsave(&zf_port_lock, flags); 197 /* stop watchdog timer */ 198 ctrl_reg = zf_get_control(); 199 ctrl_reg |= (ENABLE_WD1|ENABLE_WD2); /* disable wd1 and wd2 */ 200 ctrl_reg &= ~(ENABLE_WD1|ENABLE_WD2); 201 zf_set_control(ctrl_reg); 202 spin_unlock_irqrestore(&zf_port_lock, flags); 203 204 printk(KERN_INFO PFX ": Watchdog timer is now disabled\n"); 205 } 206 207 208 /* 209 * start hardware timer 210 */ 211 static void zf_timer_on(void) 212 { 213 unsigned int ctrl_reg = 0; 214 unsigned long flags; 215 216 spin_lock_irqsave(&zf_port_lock, flags); 217 218 zf_writeb(PULSE_LEN, 0xff); 219 220 zf_set_timer(ZF_CTIMEOUT, WD1); 221 222 /* user land ping */ 223 next_heartbeat = jiffies + ZF_USER_TIMEO; 224 225 /* start the timer for internal ping */ 226 mod_timer(&zf_timer, jiffies + ZF_HW_TIMEO); 227 228 /* start watchdog timer */ 229 ctrl_reg = zf_get_control(); 230 ctrl_reg |= (ENABLE_WD1|zf_action); 231 zf_set_control(ctrl_reg); 232 spin_unlock_irqrestore(&zf_port_lock, flags); 233 234 printk(KERN_INFO PFX ": Watchdog timer is now enabled\n"); 235 } 236 237 238 static void zf_ping(unsigned long data) 239 { 240 unsigned int ctrl_reg = 0; 241 unsigned long flags; 242 243 zf_writeb(COUNTER_2, 0xff); 244 245 if (time_before(jiffies, next_heartbeat)) { 246 dprintk("time_before: %ld\n", next_heartbeat - jiffies); 247 /* 248 * reset event is activated by transition from 0 to 1 on 249 * RESET_WD1 bit and we assume that it is already zero... 250 */ 251 252 spin_lock_irqsave(&zf_port_lock, flags); 253 ctrl_reg = zf_get_control(); 254 ctrl_reg |= RESET_WD1; 255 zf_set_control(ctrl_reg); 256 257 /* ...and nothing changes until here */ 258 ctrl_reg &= ~(RESET_WD1); 259 zf_set_control(ctrl_reg); 260 spin_unlock_irqrestore(&zf_port_lock, flags); 261 262 mod_timer(&zf_timer, jiffies + ZF_HW_TIMEO); 263 } else 264 printk(KERN_CRIT PFX ": I will reset your machine\n"); 265 } 266 267 static ssize_t zf_write(struct file *file, const char __user *buf, size_t count, 268 loff_t *ppos) 269 { 270 /* See if we got the magic character */ 271 if (count) { 272 /* 273 * no need to check for close confirmation 274 * no way to disable watchdog ;) 275 */ 276 if (!nowayout) { 277 size_t ofs; 278 /* 279 * note: just in case someone wrote the magic character 280 * five months ago... 281 */ 282 zf_expect_close = 0; 283 284 /* now scan */ 285 for (ofs = 0; ofs != count; ofs++) { 286 char c; 287 if (get_user(c, buf + ofs)) 288 return -EFAULT; 289 if (c == 'V') { 290 zf_expect_close = 42; 291 dprintk("zf_expect_close = 42\n"); 292 } 293 } 294 } 295 296 /* 297 * Well, anyhow someone wrote to us, 298 * we should return that favour 299 */ 300 next_heartbeat = jiffies + ZF_USER_TIMEO; 301 dprintk("user ping at %ld\n", jiffies); 302 } 303 return count; 304 } 305 306 static long zf_ioctl(struct file *file, unsigned int cmd, unsigned long arg) 307 { 308 void __user *argp = (void __user *)arg; 309 int __user *p = argp; 310 switch (cmd) { 311 case WDIOC_GETSUPPORT: 312 if (copy_to_user(argp, &zf_info, sizeof(zf_info))) 313 return -EFAULT; 314 break; 315 case WDIOC_GETSTATUS: 316 case WDIOC_GETBOOTSTATUS: 317 return put_user(0, p); 318 case WDIOC_KEEPALIVE: 319 zf_ping(0); 320 break; 321 default: 322 return -ENOTTY; 323 } 324 return 0; 325 } 326 327 static int zf_open(struct inode *inode, struct file *file) 328 { 329 if (test_and_set_bit(0, &zf_is_open)) 330 return -EBUSY; 331 if (nowayout) 332 __module_get(THIS_MODULE); 333 zf_timer_on(); 334 return nonseekable_open(inode, file); 335 } 336 337 static int zf_close(struct inode *inode, struct file *file) 338 { 339 if (zf_expect_close == 42) 340 zf_timer_off(); 341 else { 342 del_timer(&zf_timer); 343 printk(KERN_ERR PFX ": device file closed unexpectedly. Will not stop the WDT!\n"); 344 } 345 clear_bit(0, &zf_is_open); 346 zf_expect_close = 0; 347 return 0; 348 } 349 350 /* 351 * Notifier for system down 352 */ 353 354 static int zf_notify_sys(struct notifier_block *this, unsigned long code, 355 void *unused) 356 { 357 if (code == SYS_DOWN || code == SYS_HALT) 358 zf_timer_off(); 359 return NOTIFY_DONE; 360 } 361 362 static const struct file_operations zf_fops = { 363 .owner = THIS_MODULE, 364 .llseek = no_llseek, 365 .write = zf_write, 366 .unlocked_ioctl = zf_ioctl, 367 .open = zf_open, 368 .release = zf_close, 369 }; 370 371 static struct miscdevice zf_miscdev = { 372 .minor = WATCHDOG_MINOR, 373 .name = "watchdog", 374 .fops = &zf_fops, 375 }; 376 377 378 /* 379 * The device needs to learn about soft shutdowns in order to 380 * turn the timebomb registers off. 381 */ 382 static struct notifier_block zf_notifier = { 383 .notifier_call = zf_notify_sys, 384 }; 385 386 static void __init zf_show_action(int act) 387 { 388 char *str[] = { "RESET", "SMI", "NMI", "SCI" }; 389 390 printk(KERN_INFO PFX ": Watchdog using action = %s\n", str[act]); 391 } 392 393 static int __init zf_init(void) 394 { 395 int ret; 396 397 printk(KERN_INFO PFX 398 ": MachZ ZF-Logic Watchdog driver initializing.\n"); 399 400 ret = zf_get_ZFL_version(); 401 if (!ret || ret == 0xffff) { 402 printk(KERN_WARNING PFX ": no ZF-Logic found\n"); 403 return -ENODEV; 404 } 405 406 if (action <= 3 && action >= 0) 407 zf_action = zf_action >> action; 408 else 409 action = 0; 410 411 zf_show_action(action); 412 413 if (!request_region(ZF_IOBASE, 3, "MachZ ZFL WDT")) { 414 printk(KERN_ERR "cannot reserve I/O ports at %d\n", 415 ZF_IOBASE); 416 ret = -EBUSY; 417 goto no_region; 418 } 419 420 ret = register_reboot_notifier(&zf_notifier); 421 if (ret) { 422 printk(KERN_ERR "can't register reboot notifier (err=%d)\n", 423 ret); 424 goto no_reboot; 425 } 426 427 ret = misc_register(&zf_miscdev); 428 if (ret) { 429 printk(KERN_ERR "can't misc_register on minor=%d\n", 430 WATCHDOG_MINOR); 431 goto no_misc; 432 } 433 434 zf_set_status(0); 435 zf_set_control(0); 436 437 return 0; 438 439 no_misc: 440 unregister_reboot_notifier(&zf_notifier); 441 no_reboot: 442 release_region(ZF_IOBASE, 3); 443 no_region: 444 return ret; 445 } 446 447 448 static void __exit zf_exit(void) 449 { 450 zf_timer_off(); 451 452 misc_deregister(&zf_miscdev); 453 unregister_reboot_notifier(&zf_notifier); 454 release_region(ZF_IOBASE, 3); 455 } 456 457 module_init(zf_init); 458 module_exit(zf_exit); 459